气化渣高温预热脱碳工艺及其固相产物水泥特性试验

Experiment on high temperature preheating and decarbonization process ofcoal gasification slag and cement properties of solid phase products

气化渣是煤气化过程中产生的固体废弃物,目前主要通过填埋方式处理,不仅占用大量土地,污染土壤和水体,同时造成能源浪费。气化渣具有一定固定碳含量,但挥发分含量极低且收到基含水量很高,导致气化渣能源化利用困难。高温预热脱碳工艺是近年来发展的实现超低品位煤基固废资源化处置的有效技术途径之一,该工艺能实现近零挥发分和超低热值固废的自稳燃和燃尽过程,如处置气化渣以及灰渣污泥混合物。干基固定碳占比在13.1%~16.2%的气化渣经新疆甘泉堡工业园单线10万t/a级高温预热脱碳一体化装备处理后,挥发分基本脱除,出口灰渣残碳量均低于3%,在不添加辅助燃料条件下实现输入物料的稳定着火、高效燃尽,稳定运行出口烟气按O_(2)体积分数9%折算,NO_(x)排放在64.5~66.9 mg/m^(3)。利用工业示范生产线脱碳后气化渣及气化渣污泥混合物磨细后替代30%水泥进行胶砂制备,强度活性指数分别达到80%及91%,符合拌制砂浆和混凝土用粉煤灰以及水泥活性混合材料用粉煤灰强度活性指数要求。

Gasification slag is the solid waste produced in the process of coal gasification.At present,it is mainly treated by landfill.It not only occupies a large amount of land,pollutes soil and water,but also causes energy waste.The gasification slag has a certain carbon content,but the volatile content is very low and the water content of the receiving base is very high,which leads to the difficulty of energy utilization of the gasification slag.High temperature preheating decarbonization process is one of the effective technical approaches to realize the resource disposal of ultra-low grade coal-based solid waste developed in recent years.This process can realize the self-stable combustion and burnout process of solid waste with near zero volatile matter and ultra-low calorific value,such as gasification slag and ash sludge mixture.After the gasification slag with the proportion of dry base fixed carbon of 13.1%-16.2%is treated by the integrated equipment of 100000 tons/year high temperature preheating and decarbonization in the single line of Xinjiang Ganquanpu Industrial Park,the volatilization is basically removed,and the carbon content of exported ash residue is lower than 3%.The stable ignition and efficient burning of input materials can be achieved without adding auxiliary fuel.The flue gas at the outlet of stable operation is converted to 9% O_(2) concentration,and the NO_(x) emission is in the range of 64.5-66.9 mg/m^(3).The gasification slag and gasification slag sludge mixture after decarburization of the industrial demonstration production line are ground to replace 30%cement for mortar preparation,and the strength activity index reaches 80%and 91%respectively,meeting the requirements of the strength activity index of fly ash for mortar and concrete mixing and fly ash for cement active mixing materials.